Milestones in the search for the supermassive black hole in our Galactic center

Einstein′s theory of general relativity predicts the existence of black holes in the universe. It is now established that a compact object of four million solar masses resides at the very center of our Milky Way galaxy, which is considered as the most convincing case of an astrophysical black hole. This article aims to highlight some of the milestones toward the discovery of this massive compact object.